Dating jitters
Dating > Dating jitters
Click here: ※ Dating jitters ※ ♥ Dating jitters
Jeter made an appearance alongside to celebrate in February 2015. Morneau won the balloting with 320 points to Jeter's 306 points. dating jitters Retrieved October 4, 2009. Retrieved November 25, 2011. Retrieved April 7, 2015. Retrieved May 11, 2012. If you're sitting in the autobus thinking I wish he were holding my hand, yes take his hand. Retrieved November 19, 2011. Retrieved May 15, 2012. Retrieved September 20, 2010. If they don't, they won't. AJCs operate by re-timing the output pulses so they align more closely to an idealised pulse signal.
This article needs additional citations for. Unsourced material may be challenged and removed. March 2009 In and , jitter is the deviation from true periodicity of a presumably , often in relation to a reference. In applications it is called timing jitter. Jitter is a significant, and usually undesired, factor in the design of almost all communications links. Jitter can be quantified in the same terms as all time-varying signals, e. Also like other time-varying signals, jitter can be expressed in terms of. Jitter period is the interval between two times of maximum effect or minimum effect of a signal characteristic that varies regularly with time. Jitter frequency, the more commonly quoted figure, is its inverse. Jitter may be caused by and with carriers of other signals. Jitter can cause a display monitor to flicker, affect the performance of processors in personal computers, introduce clicks or other undesired effects in audio signals, and cause loss of transmitted data between network devices. The amount of tolerable jitter depends on the affected application. For jitter, there are three commonly used metrics: Absolute jitter The in the position of a clock's edge from where it would ideally be. Period jitter aka cycle jitter The difference between any one clock period and the ideal or average clock period. Period jitter tends to be important in synchronous circuitry such as digital state machines where the error-free operation of the circuitry is limited by the shortest possible clock period average period less maximum cycle jitter , and the performance of the circuitry is set by the average clock period. Hence, synchronous circuitry benefits from minimizing period jitter, so that the shortest clock period approaches the average clock period. Cycle-to-cycle jitter The difference in duration of any two adjacent clock periods. It can be important for some types of clock generation circuitry used in and interfaces. In , the unit used for the above types of jitter is usually the UI which quantifies the jitter in terms of a fraction of the transmission unit period. This unit is useful because it scales with clock frequency and thus allows relatively slow interconnects such as to be compared to higher-speed internet backbone links such as. Absolute units such as picoseconds are more common in microprocessor applications. Units of degrees and radians are also used. In the normal distribution one from the dark blue accounts for about 68% of the set, while two standard deviations from the mean medium and dark blue account for about 95% and three standard deviations light, medium, and dark blue account for about 99. If jitter has a , it is usually quantified using the of this distribution. This translates to a RMS measurement for a zero-mean distribution. Often, jitter distribution is significantly non-Gaussian. This can occur if the jitter is caused by external sources such as power supply noise. In these cases, peak-to-peak measurements may be more useful. Many efforts have been made to meaningfully quantify distributions that are neither Gaussian nor have a meaningful peak level. All have shortcomings but most tend to be good enough for the purposes of engineering work. Note that typically, the reference point for jitter is defined such that the jitter is 0. One of the main differences between random and deterministic jitter is that deterministic jitter is bounded and random jitter is unbounded. Random jitter Random Jitter, also called Gaussian jitter, is unpredictable electronic timing noise. The central limit theorem states that composite effect of many uncorrelated noise sources, regardless of the distributions, approaches a normal distribution. Deterministic jitter Deterministic jitter is a type of clock or data signal jitter that is predictable and reproducible. The peak-to-peak value of this jitter is bounded, and the bounds can easily be observed and predicted. Deterministic jitter has a known non-normal distribution. Deterministic jitter can either be correlated to the data stream or uncorrelated to the data stream bounded uncorrelated jitter. Examples of data-dependent jitter are duty-cycle dependent jitter also known as duty-cycle distortion and. Total jitter n BER 6. Sampling jitter In analog to digital and digital to analog conversion of signals, the sampling is normally assumed to be periodic with a fixed period—the time between every two samples is the same. If there is jitter present on the clock signal to the or a , the time between samples varies and instantaneous signal error arises. The error is proportional to the of the desired signal and the absolute value of the clock error. In some conditions, less than a nanosecond of jitter can reduce the effective bit resolution of a converter with a of 22 kHz to 14 bits. This is a consideration in high-frequency signal conversion, or where the clock signal is especially prone to interference. Packet jitter in computer networks In the context of computer networks, jitter is the variation in latency as measured in the variability over time of the packet latency across a network. A network with constant latency has no variation or jitter. Packet jitter is expressed as an average of the deviation from the network mean latency. However, for this use, the term is imprecise. PDV is an important factor in assessment of network performance. However, unlike the jitter caused by variation in latency, transmitting in bursts is commonly seen a desirable feature, e. This MBS can be derived from or used to derive the maximum variation between the arrival time of traffic in the bursts from the time it would arrive at the SCR, i. Compact disc seek jitter In the context of from , seek jitter causes extracted to be doubled-up or skipped entirely if the Compact Disc drive re-seeks. The problem occurs because the does not require block-accurate addressing during seeking. As a result, the extraction process may restart a few samples early or late, resulting in doubled or omitted samples. These glitches often sound like tiny repeating clicks during playback. A successful approach to correction in software involves performing overlapping reads and fitting the data to find overlaps at the edges. Most extraction programs perform seek jitter correction. CD manufacturers avoid seek jitter by extracting the entire disc in one continuous read operation, using special CD drive models at slower speeds so the drive does not re-seek. A jitter meter is a testing instrument for measuring clock jitter values, and is used in manufacturing and discs. Due to additional sector level addressing added in the , data discs are not subject to seek jitter. Video and image jitter Video or image jitter occurs when the horizontal lines of video image frames are randomly displaced due to the corruption of synchronization signals or electromagnetic interference during video transmission. Testing for jitter and its measurement is of growing importance to electronics engineers because of increased clock frequencies in digital electronic circuitry to achieve higher device performance. Higher clock frequencies have commensurately smaller , and thus impose tighter tolerances on jitter. For example, modern computer have serial bus architectures with eye openings of 160 or less. This is extremely small compared to parallel bus architectures with equivalent performance, which may have eye openings on the order of 1000. Testing of device performance for jitter tolerance often involves the injection of jitter into electronic components with specialized test equipment. Jitter is measured and evaluated in various ways depending on the type of circuitry under test. For example, jitter in serial bus architectures is measured by means of eye diagrams, according to industry accepted standards. A less direct approach—in which analog waveforms are digitized and the resulting data stream analyzed—is employed when measuring pixel jitter in. In all cases, the goal of jitter measurement is to verify that the jitter will not disrupt normal operation of the circuitry. There are standards for jitter measurement in serial bus architectures. The standards cover , and , with the required values for these attributes varying among different applications. Where applicable, compliant systems are required to conform to these standards. Anti-jitter circuits Anti-jitter circuits AJCs are a class of designed to reduce the level of jitter in a regular pulse. AJCs operate by re-timing the output pulses so they align more closely to an idealised pulse signal. They are widely used in clock and data recovery circuits in , as well as for data sampling systems such as the and. Examples of anti-jitter circuits include and. Inside digital to analog converters, jitter causes unwanted high-frequency distortions. In this case it can be suppressed with high fidelity clock signal usage. Jitter buffers Jitter buffers or de-jitter buffers are used to counter jitter introduced by queuing in so that a continuous playout of audio or video transmitted over the network can be ensured. The maximum jitter that can be countered by a de-jitter buffer is equal to the buffering delay introduced before starting the play-out of the mediastream. In the context of , the term is often preferred over jitter. Some systems use sophisticated delay-optimal de-jitter buffers that are capable of adapting the buffering delay to changing network jitter characteristics. These are known as adaptive de-jitter buffers and the adaptation logic is based on the jitter estimates computed from the arrival characteristics of the media packets. Adaptive de-jittering involves introducing discontinuities in the media play-out, which may appear offensive to the listener or viewer. Dejitterizer A dejitterizer is a device that reduces jitter in a. A dejitterizer usually consists of an in which the signal is temporarily stored and then retransmitted at a rate based on the average rate of the incoming signal. A dejitterizer is usually ineffective in dealing with low-frequency jitter, such as waiting-time jitter. Filtering A filter can be designed to minimize the effect of sampling jitter. For more information, see the paper by S. Decomposition Jitter signal can be decomposed into IMFs , which can be further applied for filtering or dejittering. Phase-Locked Loop Circuit Design. Archived from PDF on 2012-02-07. Retrieved 12 April 2013. Image and Vision Computing. Presented at International Test Conference 2008. Presented at DesignCon 2009. Presented at Electronics Components and Technology Conference 2009. Jitter in Digital Transmission Systems. Presented at International Test Conference 2008.
Last updated
